Improvement in hollow bolts



DAVIDE. FETTER, M.D., OF NEW YORK, N. Y. Leners PatmNo. 66,976, daad February i6, 1869.

MROVEMENT IN HOLLOW BOLTS.

' The Schedule referred to in these Letters Patent and making part of the same.

To all whom it ma/y conce/m Be it known that I,DAv1D F. FETTER, M. D., of the city, county, and State of New York, have invented a new and improved TubularBolt; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the saine, reference being had to the accompanying drawings, forming part of this specification.

Figure l represents a side view, partly in section', of my improved tubular bolt.

Figure 2 is an end view of the same.

Similar letters of reference indicate corresponding parts.

T 's invention relates to an improvement iu hollow bolts for ship-building-purposes, in which a large proportion of metal may be utilized, while it will be fully as strong as those heretofore employedt It consists in vproviding one end of the hollow bolt with a series of concentric grooves, so arranged that the bolt may be easily driven into the wood, but cannot be withdrawn.

A, in the drawings, represents a bolt made of tubur lar iron, or other suitable material, of suitable length and diameter. Ooncentric grooves, a a, are formed around it, near one end, as shown in g. 1, to make it hold in the wood. When the bolt is driven into the wood, it will enter very easy, but cannot again be withdrawn, as the sharp edges ret-ain it, harpoon-fashion,

end with a series of concentric grooves, a, which permit the boltto be easily driven into the wood, but prevent it from being withdrawn, as herein shown and described.

DAVID vF. FETTER, M. D. Witnesses:

' FRANK BLOCKLEY,

ALEX. F. RoBERTs. 

